TCP/IP optimization over wide area networks: implications for teleradiology

Radiology examinations are large. The advent of fast volume imaging is making that statement truer every year. PACS are based on the assumption of fast local networking and just-in-time image pull to the desktop. On the other hand, teleradiology has been developed on a push model to accommodate the challenges of moderate bandwidth, high-latency wide area networks (WANs). Our group faced the challenging task of creating a PACS environment that felt local, while pulling images across a 3,000-mile roundtrip WAN link. Initial tests showed WAN performance lagging local area network (LAN) performance by a factor of 30 times. A 16-month journey of explorations pulled the WAN value down to only 1.5 times slower than the LAN.